Lubricant pump



April3o,1-946. i .E w DAvfs 2,399,172-

LUBRICANT PUMP Filed Sept. ll, 1943 2 Sheets-Sheet l April 30, 1946'.

E. W. DAVIS LUBRICANT PUMPA Filed Sept. '11, 1945 l 2 Sheets-Sheet 2 Paiented pr. 30, 1946 LUBnIcAN'r y y Ernest W. Davis. River Forest, lill., assigner to Stewart-Warner Corporation, Chicago. Ill., ,a corporation of Virginia Application September lll, 1943, Serial No. 501,934

3 Claims.

My invention relates to pumps for pumping lubricant, and more particularly to pumps for pumping very heavy lubricant, wherein the cohesive force of the lubricant is so strong that atmospheric pressure alone is incapable of projecting the lubricant through the relatively long and bending inlet passageways usually provided in pumps designed for handling lubricants of ordinary consistency,

The principal object of this invention is to provide a pump of the class described which will pump very heavy lubricant .in an efllcient inanner, even when the lubricant to be pumped'is abnormally cold. Otherfobjects will appear as the description proceeds.

In the drawings- Fig. 1 is an elevation in partial section showing the lubricant pump of this invention;

Fig. 2 is a central longitudinal section of the pumping elements and associated parts;

Fig. 3 is a transverse section on the line 3--3 in Fig. 2;

Fig. 4 illustrates the inoperative performance of an ordinary grease pump when used with lubricant having unusually high viscosity, such as that which can .be handled successfully with the lubricant pump of this invention;

Fig. 5 illustrates one stage in the operation of the lubricant pump of this invention;

Fig. 6 illustrates the next succeeding the operation;

Fig. 7 illustrates a further stage of the operation; and

Fig. 8 illustrates a more advanced stage of the operation.

Referring to Fig. 1, the lubricant pump of this invention employs a container .it for holding lubricant. The container l is provided with a cover I2, which supports an air engine It for producing the reciprocating motion necessary for operating the Working parts of the pumping mechanism which will be described hereinafter. The air engine I4 is of a, general type well known to those skilled in the art, and detailed description is therefore unnecessary.

The air engine I4 is provided with the usual piston rod I6 (Fig. 2) to which ,is secured the pump piston rod I8, which extends` downwardly into the stationary cylinder 20 where it is connected with the cylinder head 22 of the movable cylinder 2t. The cylinder head 22 is provided with a number of perforations 26. The check stage of valve 28 is movable coaxially with the connect-` ing rod i8 between the cylinder head 22 and the crosspn 30. The downwardly extending por- (ci. 22a-255)" A tions 32 are integral with the stationary cylinder 2u and provide supports for positioning the stationary piston ttl, which is of a diameter that ts closely within the movable cylinder 2d.

The booster pump cylinder 3S is provided witha discharge outlet 36, and is iltted with a lapped piston t0 which. upon upward movement of the piston rod lli, engages with the check valve t2. The booster pump cylinder Se is threaded at its lower end for retaining the cap tt, which is provided with a valve seat it, against which the check valve it is seated during downward movement oijthe piston rod. it.

The follower plate 50 (Fig. 1) is maintained in a-horizontal position by the bushing 52, and is provided with turn screws te, 5t, by means of which the follower plate 5t is initially loosened from the bottom of the container it, when the lubricant is nearly exhausted from the container l.

The advantage of the construction used in this lubricant pump will be more apparent by comparing its operation with that of an ordinary pump designed for use with lubricants of ordinary consistency. The condition responsible for failure of such a pump is illustrated in Fig. 4, wherein the check valve 5t is moved to the position shown during the ilow or ordinary lubricant into the cylinder t along the paths of travel indicated by the broken lines. Such a foot valve is entirely satisfactory for use with soft lubricant that is not too cold, but is not satisfactory Ifor use with lubricant of the class that is commonly designated as brous lubricant, and especially when it is abnormally cold. Such iibrous lubricant Bt, when used with the foot valve shown in Fig. 4, has a cohesive force so strong that-atmospheric pressure canA force it into the foot valve only to the position shown, which is insufiicient 'to provide any pumping action.

Operation Atmospheric pressure acting on heavy lubri-l .'Phis results in the discharge of lubricant upwardly from the movable cylinder 2l, past the check valve 28, and into the stationary cylinder 20, as shown at the numeral 8l. The following upward movement of the movable cylinder 2l to the position shown in Fig. 8 will then iill up the void space 66 in Fig. 7, and will open a void space 68 (Fig. 8) which will be partly filled withv y lubricant 60 by the time the movable cylinder reaches its extreme uppermost position, as shown in Fig. 5. The movable cylinder 24, in moving from the position shown in Fig. 8 to the position shown in Fig. 5, will displace lubricant upward- 1y in the stationary cylinder 20, as will be readily understood.

Durlng upward movement of the movable cylinder 24, the booster pump piston 4l is also moved upwardly, thereby expelling lubricant through the discharge'outlet I8 and simultaneously providing space below the piston I0. for the inflow of v tures, it is impossible to predict the exact amount of lubricant that will be shaved oi! during downward movement of the movable cylinder 2|. In case lthe amount shaved of! is less than the normal displacement in the booster pump cylinder 36, then the resulting void spaces in the lubricant will be closed in the booster pump cylinder 36,

and the amount of lubricant discharged through the discharge outlet 3B will be somewhat less than normal. On the other hand, if the amount of lubricant shaved ofi is greater than the normal displacement in the booster pump cylinder 38, then the excess lubricant will escape downwardly past the movable cylinder 24, which fits loosely within the stationary cylinder 2|! in order to provide this action.

If the piston 40 and check valve Il are removed, the pump will then function as a low pressure pump, which construction may be of utility under some conditions o! service, such as nlling hand guns, or applying'lubricant in cavities of ample size where little pressure is required.

While the pump of this invention is described as a lubricant pump, suitable for use in handling heavy lubricants, its suitability for pumping plastic substances other than lubricants is quite obvious. i

I claim:

1. In a three stage lubricant 4pump having, a container for holding a main body of lubricant; a movable cylinder within said container; a piston for said cylinder, said piston being positioned within the space normally occupied by said main body of lubricant; means for producing reciprocating movement of said movable cylinder relative to said piston and relative to said main body of lubricant, said reciprocating movement extending between a position in which said movable cylinder is removed from said piston and a position in' which said movable cylinder surrounds said piston, whereby movement of said movable cylinder through said main Abody of lu.

bricant in a direction towards said piston, will iirst shave oil a segregated quantity of said luby; and a booster pump forv applying high pressure to said re-pumped lubricant, said booster pump being actuated by said reciprocating means, and said booster pump receiving lubricant from said secondary pumping means.

2. In a lubricant pump, having a container for holding a main body of lubricant; a stationary cylinder extending downwardly in said container and terminating some distance from the bottom of said container; a stationary piston positioned in axial alignment with said stationary cylinder at an elevation below the lower end of said stationary cylinder; a movable cylinder slidable inside or said stationary cylinder to a position above said piston and to a position surrounding said piston: means for restricting downward flow of lubricant from said stationary cylinder and past said movable cylinder; and means for reciprocating said movable cylinder between a position in which said movable cylinder is removed from said piston and a position in which said movable cylinder surrounds said piston, whereby movement oi said movable cylinder through said main body of lubricant in a direction towards said piston, will iirst 'shave ofi a segregated quantity of said lubricant, and whereby continued movement of said movable cylinder to a position l surrounding said piston, will then displace said segregated lubricant upwardly in said movable cylinder, thereby discharging lubricant from said movable cylinder into said stationary cylinder, and whereby succeeding upward movement oi said movable cylinder will then displace said discharged lubricant upwardly within said stationary cylinder.

3. In a lubricant pump having, a container iol holding lubricant; a stationary cylinder extending downwardly in said container and terminating some distance from the bottom thereof; a plurality of extending portions connected with said stationary cylinder and extending downwardly in said container; a stationary piston supported by said extending portions; a movable cylinder coaxial with said stationary cylinder and slidable therein to an upper position in which said piston is exposed to said lubricant, and to a lower position in which said movable cylinder surrounds said piston; means for preventing downward flow oi lubricant through said movable cylinder; and means for reciprocating said movable cylinder between said upper position and said lower position, whereby initial downward move- -ment of said movable cylinder through said lubricant will first shave off and segregate those portions of said lubricant which Aprotrude inwardly between said extending' portions, and whereby continued downward movement of said movable cylinder to said lower position, will displace said segregated portions` of lubricant up- ERNEST W. DAVIS. 

